Multi chip module housing mounting in MWD, LWD and wireline downhole tool assemblies

FIELD OF THE DISCLOSURE

This disclosure pertains generally to devices and methods for providing shock and vibration protection for borehole devices.

BACKGROUND OF THE DISCLOSURE

Exploration and production of hydrocarbons generally requires the use of various tools that are lowered into a borehole, such as drilling assemblies, measurement tools and production devices (e.g., fracturing tools). Electronic components may be disposed downhole for various purposes, such as control of downhole tools, communication with the surface and storage and analysis of data. Such electronic components typically include printed circuit boards (PCBs) that are packaged to provide protection from downhole conditions, including temperature, pressure, vibration and other thermo-mechanical stresses.

In one aspect, the present disclosure addresses the need for enhanced shock and vibration protection for electronic components and other shock and vibration sensitive devices used in a borehole.

SUMMARY OF THE DISCLOSURE

In aspects, the present disclosure provides an apparatus for protecting an electronics module used in a borehole. The apparatus may include a section of a borehole string having an outer circumferential surface on which at least one pocket is formed, a mount associated with the at least one pocket, and a sleeve surrounding the section of the borehole string. The mount may include a housing, a lid, and a biasing member. The housing receives the electronics module and is seated on a seating surface of the at least one pocket. The lid encloses the housing within the at least one pocket. The biasing member is positioned between the lid and the housing. The sleeve may press the lid against the biasing member and the biasing member may responsively urge the housing against the seating surface.

In further aspects, the present disclosure also provides an apparatus for protecting electronics modules used in a borehole where the apparatus includes a borehole string section having an outer circumferential surface on which a plurality of pockets are circumferentially distributed, a mount associated with each pocket, and a sleeve. Each mount may include a heat transfer pad positioned on a seating surface of each pocket, a housing receiving and hermetically sealing an associated electronics module, the housing being seated on the heat transfer pad, a lid enclosing the housing within the associated pocket, and a biasing member positioned between the lid and the housing. The sleeve surrounds the borehole string section and secures each lid of each mount within the associated pocket. The sleeve interfering engages each lid to compress the associated biasing member and each biasing member responsively urges the associated housing against the associated heat transfer pad. Also, each pocket may include at least one passage connecting each pocket to a compartment in the borehole section for receiving electrical equipment.

In aspects, the present disclosure also provides a method for protecting a module used in a borehole. The method may include forming at least one pocket in an outer circumferential surface of a section of a borehole string; and disposing a mount at least partially into the at least one pocket. The mount may include a housing receiving the electronics module, the housing being seated on a seating surface of the at least one pocket, a lid enclosing the housing within the at least one pocket, a biasing member positioned between the lid and the housing, and a sleeve surrounding the section of the borehole string. The method also includes securing the lid within the at least one pocket by using the sleeve to press the lid against the biasing member, which responsively urges the housing against the seating surface.

Examples of certain features of the disclosure have been summarized rather broadly in order that the detailed description thereof that follows may be better understood and in order that the contributions they represent to the art may be appreciated.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed understanding of the present disclosure, reference should be made to the following detailed description of the embodiments, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals, wherein:

<figref idref="DRAWINGS">FIG. 1</figref> shows a schematic of a well system that may use one or more mounts according to the present disclosure;

<figref idref="DRAWINGS">FIG. 2</figref> illustrates one embodiment of an electronics module that may be protected using a mount according to the present disclosure;

<figref idref="DRAWINGS">FIG. 3</figref> illustrates an end view of a section of a BHA that has a plurality of electronics protected by mounts according to one embodiment of the present disclosure;

<figref idref="DRAWINGS">FIG. 4</figref> illustrates a sectional view of a section of the BHA that includes a mount according to one embodiment of the present disclosure; and

<figref idref="DRAWINGS">FIG. 5</figref> illustrates a latching arrangement that may be used with a mount according to one embodiment of the present disclosure.

DETAILED DESCRIPTION

Drilling conditions and dynamics produce sustained and intense shock and vibration events. These events can induce electronics failure, fatigue, and accelerated aging in the devices and components used in a drill string. In aspects, the present disclosure provides mountings and related methods for protecting these components from the energy associated with such shock events.

Referring now to <figref idref="DRAWINGS">FIG. 1</figref>, there is shown one illustrative embodiment of a drilling system <b>10</b> utilizing a borehole string <b>12</b> that may include a bottomhole assembly (BHA) <b>14</b> for directionally drilling a borehole <b>16</b>. While a land-based rig is shown, these concepts and the methods are equally applicable to offshore drilling systems. The borehole string <b>12</b> may be suspended from a rig <b>20</b> and may include jointed tubulars or coiled tubing. In one configuration, the BHA <b>14</b> may include a drill bit <b>15</b>, a sensor sub <b>32</b>, a bidirectional communication and power module (BCPM) <b>34</b>, a formation evaluation (FE) sub <b>36</b>, and rotary power devices such as drilling motors <b>38</b>. The sensor sub <b>32</b> may include sensors for measuring near-bit direction (e.g., BHA azimuth and inclination, BHA coordinates, etc.) and sensors and tools for making rotary directional surveys. The system may also include information processing devices such as a surface controller <b>50</b> and/or a downhole controller <b>42</b>. Communication between the surface and the BHA <b>14</b> may use uplinks and/or downlinks generated by a mud-driven alternator, a mud pulser and/or conveyed using hard wires (e.g., electrical conductors, fiber optics), acoustic signals, EM or RF.

One or more electronics modules <b>24</b> incorporated into the BHA <b>14</b> or other component of the borehole string <b>12</b> may include components as necessary to provide for data storage and processing, communication and/or control of the BHA <b>14</b>. These components may be disposed in suitable compartments formed in or on the borehole string <b>12</b>. Exemplary electronics in the electronics module include printed circuit board assemblies (PCBA) and multiple chip modules (MCM's).

Referring to <figref idref="DRAWINGS">FIG. 2</figref>, there is shown one non-limiting embodiment of a module <b>24</b> that may be used with the borehole string <b>12</b> of <figref idref="DRAWINGS">FIG. 1</figref>. The module <b>24</b> can be a BHA's tool instrument module, which can be a crystal pressure or temperature detection, or frequency source, a sensor acoustic, gyro, accelerometer, magnetometer, etc., sensitive mechanical assembly, MEM, multichip module MCM, Printed circuit board assembly PCBA, flexible PCB Assembly, Hybrid PCBA mount, MCM with laminate substrate MCM-L, multichip module with ceramic substrate e.g. LCC or HCC, compact Integrated Circuit IC stacked assemblies with ball grid arrays or copper pile interconnect technology, etc. All these types of modules <b>24</b> often are made with fragile and brittle components which cannot take bending and torsion forces and therefore benefit from the protection of the package housing and layered protection described below.

Exemplary mounts for protecting shock and vibration sensitive equipment such as the electronics module <b>24</b> are described below. Although the embodiments described herein are discussed in the context of electronics modules, the embodiments may be used in conjunction with any component that would benefit from a structure having high damping, high thermal conduction, and/or low fatigue stress. Furthermore, although embodiments herein are described in the context of downhole tools, components and applications, the embodiments are not so limited.

<figref idref="DRAWINGS">FIG. 3</figref> schematically illustrates a mount <b>100</b> for protecting a module <b>24</b> (<figref idref="DRAWINGS">FIG. 2</figref>) from shock and vibration. The mount <b>100</b> may be formed in a section <b>102</b> of the borehole string <b>12</b> of <figref idref="DRAWINGS">FIG. 1</figref>. For example, the section <b>102</b> may be a drill collar, a sub, a portion of a jointed pipe, or the BHA <b>14</b>. The mount <b>100</b> may be secured within a pocket <b>104</b> formed on an outer circumferential surface <b>106</b> of the section <b>102</b>. A sleeve <b>110</b> surrounds the section <b>102</b> secures the mounts <b>100</b> within the pockets <b>104</b>. The sleeve <b>110</b> may be formed of a non-magnetic material such as stainless steel. While four mounts <b>100</b> are shown circumferentially distributed on the section <b>102</b>, it should be understood that greater or fewer number of mounts <b>100</b> may be used. In embodiments, one common continuous sleeve <b>110</b> secures a plurality of circumferentially distributed mounts <b>100</b>.

<figref idref="DRAWINGS">FIG. 4</figref> sectionally illustrates one embodiment of a mount <b>100</b> that may be used to resiliently secure the module <b>24</b> (<figref idref="DRAWINGS">FIG. 2</figref>) within the pocket <b>104</b>. The pocket <b>104</b> may be pre-formed or machined (e.g., milled) into the section <b>102</b> and include passages <b>108</b> for wiring and other equipment that connect to the module <b>24</b> (<figref idref="DRAWINGS">FIG. 2</figref>). The passages <b>108</b> may connect the pocket <b>104</b> with other compartments, chambers, or cavities that contain electrical equipment such as sensors (not shown). The mount <b>100</b> may include a housing <b>120</b>, a lid <b>130</b>, and a biasing member <b>140</b>.

The housing <b>120</b> provides a hermetically sealed environment for the module <b>24</b> (<figref idref="DRAWINGS">FIG. 2</figref>). The housing <b>120</b> may include a sealed casing <b>122</b> formed of a metal such as titanium or Kovar. These types of metals have a thermal expansion similar to the ceramic, glass, composite, or other material used to encase the module <b>24</b> (<figref idref="DRAWINGS">FIG. 2</figref>). Electrical connections to the module <b>24</b> may be made using the internal connectors <b>124</b> and the external connectors <b>126</b>. It should be understood that the shown configuration for the housing <b>120</b> is merely one non-limiting example of a housing <b>120</b> that may be used in connection with mounts <b>100</b> according to the present disclosure.

The lid <b>130</b> encloses the housing <b>120</b> within the pocket <b>104</b>. The lid <b>130</b> may include a recess <b>132</b> for receiving the biasing element <b>140</b> and the housing <b>120</b>. The recess <b>132</b> may include a shoulder <b>134</b> or other similar feature that contacts the housing <b>120</b> to minimize movement in the axial direction. As used herein, the term axial refers to a longitudinal directional along the borehole string <b>12</b> (<figref idref="DRAWINGS">FIG. 1</figref>). Referring to <figref idref="DRAWINGS">FIG. 5</figref>, the lid <b>130</b> may optionally include latches <b>136</b> that secure the lid <b>130</b> within the pocket <b>104</b>. The latches <b>136</b> may be positioned at an end <b>138</b> of the lid <b>30</b> and include spring-biased balls or other locking mechanisms engage a suitable profile <b>137</b> formed in the pocket <b>104</b>. The lid <b>130</b> may be formed of a suitable non-magnetic material such as stainless steel. Additionally, the lid <b>130</b> may include a ramped or sloped portions <b>139</b> that allow the sleeve <b>110</b> to slide over the lid <b>130</b> during final installation.

The biasing member <b>140</b> applies a spring force that presses the housing <b>120</b> against a seating surface <b>128</b> of the pocket <b>104</b>. The biasing member <b>140</b> may be any structure that has range of elastic deformation sufficient to generate a persistent spring force. As shown, the biasing member <b>140</b> may be a leaf spring that has one or more apex regions <b>142</b> that compressively contact the housing <b>120</b>. While the apex regions <b>142</b> are shown in a medial section of the biasing member <b>140</b>, it should be understood that the apex regions <b>142</b> may distributed throughout the biasing member <b>140</b>. For instance, apex regions <b>142</b> may be located at a distal end <b>144</b> of the biasing member <b>120</b>. Other springs such as coil springs or spring washers, may be used. Additionally, pressurized fluids may be used to generate a spring force. Also, while point contacts are shown, it should be understood that the biasing member <b>140</b> may be formed as a body such as a pad that distributes compressive force of a relatively large surface area. The biasing member <b>140</b> may be retained in a suitable groove or slot in the recess <b>132</b>.

Some embodiments may include a heat transfer pad <b>160</b> positioned between the housing <b>120</b> and the seating surface <b>128</b>. One non-limiting embodiment of a heat transfer pad <b>160</b> may be formed at least partially of a visco-elastic material. As used herein, a viscoelastic material is a material having both viscous and elastic characteristics when undergoing deformation. More generally, the heat transfer pad <b>160</b> may be formed of any material that transfers heat from the housing <b>120</b> to the section <b>102</b> and/or provides shock absorption.

It should be understood that the mounts according to the present disclosure are susceptible to numerous variants. For example, circumferential springs may be used to fix the mounts inside the pocket.

Referring not to <figref idref="DRAWINGS">FIGS. 1-5</figref>, in one mode of use, each module <b>24</b> is first inserted into a housing <b>120</b>. The internal electrical connections <b>124</b> are made up and the housing <b>120</b> is hermetically sealed. Next, the housing <b>120</b> is disposed into the pocket <b>104</b> and wires (not shown) are connected to the external electrical connections <b>126</b>. The lid <b>130</b> and biasing member <b>140</b> are then set over the housing <b>120</b>. Depressing the lid <b>130</b> allows the latching members <b>136</b> to snap the lid <b>130</b> into place in the pocket <b>104</b>. After all the modules <b>24</b> are installed, the sleeve <b>110</b> is slid over the pockets <b>104</b>. The sleeve <b>110</b> interferingly engages the lid <b>130</b> because an inner surface of the sleeve <b>110</b> is more radially inward that an outer surface of the lid <b>130</b> when the lid <b>130</b> rests on a relaxed biasing member <b>140</b>. This interfering engagement forces the lid <b>130</b> move radially inward, which compresses the biasing member <b>140</b>. In response to being compressed, the biasing member <b>140</b> presses the housing <b>120</b> against the heat transfer pad <b>160</b>. Thus, the module <b>24</b> is restrained against lateral motion; i.e., motion transverse to the longitudinal axis of the tool. Additionally, the shoulder <b>134</b> of the lid <b>130</b> and frictional forces at the heat transfer pad <b>160</b> minimize movement of the housing <b>130</b> in the axial direction or sliding motion generally.

During drilling or other activities in the borehole <b>16</b>, the section <b>102</b> may encounter shocks and vibrations. Advantageously, the mount <b>100</b> minimizes movement of the housing <b>120</b> and enclosed module <b>24</b> in the lateral and axial directions when subjected to these movements. Also, the heat transfer pad <b>160</b> conducts heat from the housing <b>120</b> to a suitable heat sink, such as a drilling mud flowing in the borehole string <b>12</b>.

While the foregoing disclosure is directed to the one mode embodiments of the disclosure, various modifications will be apparent to those skilled in the art. It is intended that all variations be embraced by the foregoing disclosure.